#101
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Bottle holder
On 5/23/2019 10:33 PM, John B. Slocomb wrote:
On Thu, 23 May 2019 18:17:29 -0500, AMuzi wrote: On 5/23/2019 6:04 PM, John B. Slocomb wrote: On Thu, 23 May 2019 06:56:28 -0700, sms wrote: On 5/23/2019 3:34 AM, John B. Slocomb wrote: snip No, sorry, they didn't teach us about stress concentrations when drilling holes, primarily because any hole is a stress concentration, at least to some extent. And it is illogical to think that one can change "fatigue life" by drilling a hole in some special manner. It is not illogical at all. It is a fact. There is just no way that any course in machining would not teach about how to reduce stress concentration of holes drilled into metal. You might want to ask for a partial refund if that school is still in existence. Well, I can only comment that in my career I drilled holes in just about everything that flew and much of that was specified in either manufacturer's designs and/or specifications from people who had been assigned to design and document a modification and I cannot remember ever seeing any specifications, or directions, or other data intended to tell me how to change "fatigue life" by drilling a hole in some specific manner. So kindly teach me. But before you get off your podium please remember that we are not talking about designing a hole, or placing a hole or any other fuzzy example that you may care to elaborate on. We are discussing the drilling, or boring of a cylindrical passageway through a base material. We just had a spectacular example of the result of improper drilling of holes in steel beams in San Francisco, but these were not drilled by journeyman machinists. I assume that you are referring to the following https://www.nbcbayarea.com/investiga...494862071.html If so than once again you demonstrate that you simply do not know what you are talking about and apparently haven't even bothered to take the time to "read up" on what you are trying to say. The "holes you are talking about aren't drilled, i.e. cylindrical, holes but are , apparently, cut "holes" as described in the article, that you obviously didn't read, which says, "It's not a good structural element, says mechanical engineer Bernard Cuzzillo, referring to rectangular notches clearly cut in the four-inch thick steel at the bottom of the 85-foot long I-beam used to support the terminal deck across Fremont Street. Please note, "RECTANGULAR NOTCHES" not drilled holes. Unless, of course, you anticipate cutting rectangular holes to install the cylindrical revnuts. For God's Sake! They even had a video that clearly showed the cut, angular, holes... and you didn't even bother to watch the movie. Square apertures like a DeHavilland Comet? What could go wrong? I'm working from memory now (an always hazardous undertaking) but I think that the problem with the Comet wasn't so much the window shape so much as the fuselage expanding and contracting when pressurized. Apparently that had never been a problem with previous aircraft. After all, more modern airplanes have essentially square windows :-) Huh? That's not right. https://media.cntraveller.in/wp-cont...x-8-window.jpg I don't think there are any, not in the last 40 years anyway. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
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#102
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Bottle holder
On Fri, 24 May 2019 15:18:59 +0700, John B.
wrote: One of the A.F. machine shops I was assigned to had no drill sharpening "utensils" what so ever as the Shop Chief, a grizzled old fellow that did his apprenticeship at Morse Twist Drill, I believe, said that sharpening a drill was such a basic skill that everybody must know how to do it. :-) Reminds me of the time I bought a booklet called something like "Tools and their Uses". Since it was intended for Navy inductees who didn't know anything, I figured it would tell me how to sharpen a pocket knife. All it said about pocket knives was that they should be kept sharp. -- Joy Beeson joy beeson at comcast dot net http://wlweather.net/PAGEJOY/ |
#103
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Bottle holder
On Friday, May 24, 2019 at 5:19:42 AM UTC-4, sms wrote:
On 5/24/2019 1:05 AM, John B. wrote: snip Further to Jobst's comments. I'm afraid I know many people who see no problems what so ever in drilling holes in frames - literally every custom frame builder I have ever been in contact with will put as many bottle cages on your new bike as you ask for. And every cage requires two holes to mount. Hopefully you realize the difference between a custom frame builder drilling a frame for cage mounts and the owner of a Huffy doing the same. The former almost certainly has jigs for the task and is able to put in the mounts prior to assembling and painting the frame. If it's a steel or titanium frame, which is much more likely to be the case for a custom frame builder, then they're probably brazing on the mounts, not using Rivnuts. Man you are so absolutely dense when it comes to Rivnuts! Just about anyone can drill 2 holes in an aluminium bicycle frame tube or in a steel bicycle frame and install a Rivnut in each hole without destroying or seriously weakening the frame. In fact and practice a Rivnut can be installed with nothing more than a bolt, a nut and either an Allen/Hex key or wrench depending on the type of head on the bolt. To pretend that this can NOT be done by the average person is just plain lying through your teeth. But then again, that DOES seem to be your usual method of operation. Cheers |
#104
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Bottle holder
On Fri, 24 May 2019 02:19:37 -0700, sms
wrote: On 5/24/2019 1:05 AM, John B. wrote: snip Further to Jobst's comments. I'm afraid I know many people who see no problems what so ever in drilling holes in frames - literally every custom frame builder I have ever been in contact with will put as many bottle cages on your new bike as you ask for. And every cage requires two holes to mount. Hopefully you realize the difference between a custom frame builder drilling a frame for cage mounts and the owner of a Huffy doing the same. Well, tell us, oh great pundit. Do the frame builders, who often know very little about the metals that they work with, buy special tubes to allow them to drill holes in them? Does Columbus, for example, manufacturer special frame tubes for those who wish to mount bottle cages? Or does Huffy buy special tubes that are specified by the maker NOT to be drilled? In another post I believe you made a statement that you posted about things that you knew about, so please tell us when and when not to drill holes to mount bottle cages. The former almost certainly has jigs for the task and is able to put in the mounts prior to assembling and painting the frame. If it's a steel or titanium frame, which is much more likely to be the case for a custom frame builder, then they're probably brazing on the mounts, not using Rivnuts. Actually, I wonder if you know what you are talking about? Titanium is a rather difficult metal to work with and at elevated temperatures reacts with air by bursting into flame. It can be welded using MIG with sufficient gas flow but cannot be welded with an open flame... Let me give you some information from https://www.thefabricator.com/articl...ou-can-weld-it Any time the metal reaches a temperature of 900 to 1,000 degrees F, brittle oxygen-stabilized alpha phase (or \u03b1-case) can form not only on the weld surface and its back side, but also on grinding tools2. Frictional heat, especially from aluminum oxide (Al2O3) wheels, can create high enough temperatures to embrittle the surface. Carbide-grit wheels are better because they have no aluminum to contaminate the weld. A gentle touch is best, because titanium has a low thermal conductivity and needs to be kept below the 500 degree F mark, where scaling begins. ---------- Note that most brazing done on bicycle frames is done with either silver solder - melting point in the 450 F degree region - or brass - ~850 F - which is hot enough to cause very significant changes in a titanium parent metal. So, yes, one can braze titanium but only if it is done in an inert atmosphere. I doubt and many, if any, frame maker has an inert atmosphere box large enough to hold a bicycle and thus probably brazed fittings on a titanium bicycle frame are rare enough the be non existent. -- cheers, John B. |
#105
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Bottle holder
On Fri, 24 May 2019 02:24:00 -0700, sms
wrote: On 5/24/2019 1:28 AM, John B. wrote: snip Back in the day, we were taught to deburr everything we did and most machinists kept a flat, single cut, file and a triangular scrapper in the top of his box and before you took the piece out of the machine you hit every shoulder with the file and the edges of every hole with the scrapper. Well even without going to machinists school, deburring edges and holes is a pretty obvious thing that most people know to do. I see... and you think that "most people" have a flat file and a triangular scrapper right there in their tool box? -- cheers, John B. |
#106
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Bottle holder
On 5/24/2019 6:16 PM, John B. wrote:
On Fri, 24 May 2019 02:19:37 -0700, sms wrote: On 5/24/2019 1:05 AM, John B. wrote: snip Further to Jobst's comments. I'm afraid I know many people who see no problems what so ever in drilling holes in frames - literally every custom frame builder I have ever been in contact with will put as many bottle cages on your new bike as you ask for. And every cage requires two holes to mount. Hopefully you realize the difference between a custom frame builder drilling a frame for cage mounts and the owner of a Huffy doing the same. Well, tell us, oh great pundit. Do the frame builders, who often know very little about the metals that they work with, buy special tubes to allow them to drill holes in them? Does Columbus, for example, manufacturer special frame tubes for those who wish to mount bottle cages? Or does Huffy buy special tubes that are specified by the maker NOT to be drilled? In another post I believe you made a statement that you posted about things that you knew about, so please tell us when and when not to drill holes to mount bottle cages. The former almost certainly has jigs for the task and is able to put in the mounts prior to assembling and painting the frame. If it's a steel or titanium frame, which is much more likely to be the case for a custom frame builder, then they're probably brazing on the mounts, not using Rivnuts. Actually, I wonder if you know what you are talking about? Titanium is a rather difficult metal to work with and at elevated temperatures reacts with air by bursting into flame. It can be welded using MIG with sufficient gas flow but cannot be welded with an open flame... Let me give you some information from https://www.thefabricator.com/articl...ou-can-weld-it Any time the metal reaches a temperature of 900 to 1,000 degrees F, brittle oxygen-stabilized alpha phase (or \u03b1-case) can form not only on the weld surface and its back side, but also on grinding tools2. Frictional heat, especially from aluminum oxide (Al2O3) wheels, can create high enough temperatures to embrittle the surface. Carbide-grit wheels are better because they have no aluminum to contaminate the weld. A gentle touch is best, because titanium has a low thermal conductivity and needs to be kept below the 500 degree F mark, where scaling begins. ---------- Note that most brazing done on bicycle frames is done with either silver solder - melting point in the 450 F degree region - or brass - ~850 F - which is hot enough to cause very significant changes in a titanium parent metal. So, yes, one can braze titanium but only if it is done in an inert atmosphere. I doubt and many, if any, frame maker has an inert atmosphere box large enough to hold a bicycle and thus probably brazed fittings on a titanium bicycle frame are rare enough the be non existent. -- cheers, John B. The first several years of titanium frames were indeed welded in inert-gas booths. Not very different from a bicycle frame glass bead booth really. Modern shielded-arc systems with inert gas flowing inside the tubes is the standard practice now. Oh and I think you mistyped silver braze temps, usually 1100F &up, and brazing temps roughly 1600F and up. 450 degrees F is in the cookie-baking zone, even below my lead work. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#107
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Bottle holder
On 5/24/2019 6:18 PM, John B. wrote:
On Fri, 24 May 2019 02:24:00 -0700, sms wrote: On 5/24/2019 1:28 AM, John B. wrote: snip Back in the day, we were taught to deburr everything we did and most machinists kept a flat, single cut, file and a triangular scrapper in the top of his box and before you took the piece out of the machine you hit every shoulder with the file and the edges of every hole with the scrapper. Well even without going to machinists school, deburring edges and holes is a pretty obvious thing that most people know to do. I see... and you think that "most people" have a flat file and a triangular scrapper right there in their tool box? Among those with a Kennedy tool box, yes and yes. Love this little Israeli deburr: http://www.bartsupply.com/gallery/pr...haviv_tool.jpg and a couple of Diamond Debs too. That said, "most people" probably have a crappy claw hammer, a screwdriver with flat/Phillips #2 flipover from the $1 table and a can opener. They don't know how to use the can opener. This is based on my research of being asked to help out with various household problems at various households. Based on those experiences, "no" is usually the best response. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#108
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Bottle holder
On Fri, 24 May 2019 07:55:44 -0500, AMuzi wrote:
On 5/23/2019 10:33 PM, John B. Slocomb wrote: On Thu, 23 May 2019 18:17:29 -0500, AMuzi wrote: On 5/23/2019 6:04 PM, John B. Slocomb wrote: On Thu, 23 May 2019 06:56:28 -0700, sms wrote: On 5/23/2019 3:34 AM, John B. Slocomb wrote: snip No, sorry, they didn't teach us about stress concentrations when drilling holes, primarily because any hole is a stress concentration, at least to some extent. And it is illogical to think that one can change "fatigue life" by drilling a hole in some special manner. It is not illogical at all. It is a fact. There is just no way that any course in machining would not teach about how to reduce stress concentration of holes drilled into metal. You might want to ask for a partial refund if that school is still in existence. Well, I can only comment that in my career I drilled holes in just about everything that flew and much of that was specified in either manufacturer's designs and/or specifications from people who had been assigned to design and document a modification and I cannot remember ever seeing any specifications, or directions, or other data intended to tell me how to change "fatigue life" by drilling a hole in some specific manner. So kindly teach me. But before you get off your podium please remember that we are not talking about designing a hole, or placing a hole or any other fuzzy example that you may care to elaborate on. We are discussing the drilling, or boring of a cylindrical passageway through a base material. We just had a spectacular example of the result of improper drilling of holes in steel beams in San Francisco, but these were not drilled by journeyman machinists. I assume that you are referring to the following https://www.nbcbayarea.com/investiga...494862071.html If so than once again you demonstrate that you simply do not know what you are talking about and apparently haven't even bothered to take the time to "read up" on what you are trying to say. The "holes you are talking about aren't drilled, i.e. cylindrical, holes but are , apparently, cut "holes" as described in the article, that you obviously didn't read, which says, "It's not a good structural element, says mechanical engineer Bernard Cuzzillo, referring to rectangular notches clearly cut in the four-inch thick steel at the bottom of the 85-foot long I-beam used to support the terminal deck across Fremont Street. Please note, "RECTANGULAR NOTCHES" not drilled holes. Unless, of course, you anticipate cutting rectangular holes to install the cylindrical revnuts. For God's Sake! They even had a video that clearly showed the cut, angular, holes... and you didn't even bother to watch the movie. Square apertures like a DeHavilland Comet? What could go wrong? I'm working from memory now (an always hazardous undertaking) but I think that the problem with the Comet wasn't so much the window shape so much as the fuselage expanding and contracting when pressurized. Apparently that had never been a problem with previous aircraft. After all, more modern airplanes have essentially square windows :-) Huh? That's not right. https://media.cntraveller.in/wp-cont...x-8-window.jpg I don't think there are any, not in the last 40 years anyway. Hmmm... a bit of face saving is in order :-) See https://www.youtube.com/watch?v=2ZZ0qyXNOV4 or even https://tinyurl.com/y3tgdhrw -- cheers, John B. |
#109
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Bottle holder
On Fri, 24 May 2019 11:16:37 -0400, Joy Beeson
wrote: On Fri, 24 May 2019 15:18:59 +0700, John B. wrote: One of the A.F. machine shops I was assigned to had no drill sharpening "utensils" what so ever as the Shop Chief, a grizzled old fellow that did his apprenticeship at Morse Twist Drill, I believe, said that sharpening a drill was such a basic skill that everybody must know how to do it. :-) Reminds me of the time I bought a booklet called something like "Tools and their Uses". Since it was intended for Navy inductees who didn't know anything, I figured it would tell me how to sharpen a pocket knife. All it said about pocket knives was that they should be kept sharp. Good Lord! And you a married woman? and you don't know how to sharpen a knife? You just say, "Honey, this knife is sooo dull that I can't cut this steak meat... would you like hamburger for supper? -- cheers, John B. |
#110
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Bottle holder
On Fri, 24 May 2019 10:34:21 -0700 (PDT), Sir Ridesalot
wrote: On Friday, May 24, 2019 at 5:19:42 AM UTC-4, sms wrote: On 5/24/2019 1:05 AM, John B. wrote: snip Further to Jobst's comments. I'm afraid I know many people who see no problems what so ever in drilling holes in frames - literally every custom frame builder I have ever been in contact with will put as many bottle cages on your new bike as you ask for. And every cage requires two holes to mount. Hopefully you realize the difference between a custom frame builder drilling a frame for cage mounts and the owner of a Huffy doing the same. The former almost certainly has jigs for the task and is able to put in the mounts prior to assembling and painting the frame. If it's a steel or titanium frame, which is much more likely to be the case for a custom frame builder, then they're probably brazing on the mounts, not using Rivnuts. Man you are so absolutely dense when it comes to Rivnuts! Just about anyone can drill 2 holes in an aluminium bicycle frame tube or in a steel bicycle frame and install a Rivnut in each hole without destroying or seriously weakening the frame. In fact and practice a Rivnut can be installed with nothing more than a bolt, a nut and either an Allen/Hex key or wrench depending on the type of head on the bolt. To pretend that this can NOT be done by the average person is just plain lying through your teeth. But then again, that DOES seem to be your usual method of operation. Cheers I suspect that SMS is so awkward that he couldn't even imagine attempting to drill two holes, and being, in his own mind the perfect person, it is patently obvious that it is impossible for anyone else to accomplish this monumental task. Given that, if this humble task should become a common practice, it would demonstrate that SMS is not the all wise, all knowing, individual that he imagines himself to be and so he must belittle any and all that claim the feat is possible. -- cheers, John B. |
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